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Old March 24th 10, 06:12 PM posted to sci.electronics.design,rec.radio.amateur.homebrew
dave.harper dave.harper is offline
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First recorded activity by RadioBanter: Mar 2009
Posts: 8
Default Square wave to psuedo-sine wave?

On Mar 24, 9:06*am, Uwe Hercksen wrote:
dave.harper schrieb:

Originally, I had used a wein-bridge oscillator with op-amps to make
the sine wave, but due to the environment, EMI was a problem and it
damped out the oscillations (even with ferrite beads and modest
shielding). *So I'd like to avoid using op-amps (since they are
apparently sensitive to EMI) if possible.


Hello,

a Wien-Robinson bridge oscillator needs a good amplitude stabilisation.
If the amplification is to low, the oscillations will damp out. I guess
there was something wrong with your amplitude stabilisation.

Bye


No, I used non-linear feedback (diodes) and it worked like a champ. O-
scope showed a nice, rounded, stable wave with no clipping. It was
only when the nearby transmitter was turned on, the oscillations
damped out.

Dave